SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd9ee212cce712228935bdd991a48baee16cff6c81148d2c6f81ff4eb85c85fd' 
  AND token = 'MpiTrXGhaU0RvliZuElHNH85upoEnPAIoXUZ0MwjwRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}